Introduction
Ammonia is a chemical compound with the formula NH3. It is a colorless gas with a pungent odor and is classified as a base. However, unlike other bases, ammonia does not contain a hydroxyl group (-OH).

Explanation
A base is a substance that can accept a proton (H+) from an acid to form a salt and water. Bases are also known as proton acceptors. In contrast, acids are proton donors. Bases can be classified into two types: Arrhenius bases and Bronsted-Lowry bases.

- Arrhenius bases are substances that produce hydroxide ions (OH-) in water. Examples include NaOH, KOH, and Ca(OH)2.
- Bronsted-Lowry bases are substances that can accept a proton (H+) from an acid. They can also be defined as substances that donate an electron pair to form a covalent bond with a proton. Examples include NH3, HCO3-, and H2PO4-.

Why is ammonia a base?
Ammonia is a base because it can accept a proton (H+) from an acid to form a salt and water. The NH3 molecule has a lone pair of electrons on the nitrogen atom, which can accept a proton from an acid. When ammonia accepts a proton, it forms the ammonium ion (NH4+).

NH3 + H+ → NH4+

The reaction above shows how ammonia accepts a proton (H+) to form the ammonium ion.

Why doesn't ammonia contain a hydroxyl group?
Ammonia does not contain a hydroxyl group (-OH) because it is not a hydroxide compound. Hydroxides are compounds that contain the hydroxyl group (-OH). For example, NaOH and KOH are hydroxides because they contain the hydroxyl group.

In ammonia, the nitrogen atom is bonded to three hydrogen atoms and has a lone pair of electrons. It does not contain a hydroxyl group (-OH). Therefore, ammonia is not a hydroxide compound, but it is still a base because it can accept a proton (H+) from an acid.

Conclusion
In summary, ammonia is a base because it can accept a proton (H+) from an acid to form a salt and water. However, unlike other bases, ammonia does not contain a hydroxyl group (-OH). The lone pair of electrons on the nitrogen atom allows ammonia to accept a proton and form the ammonium ion.

Give reason - ammonia is a base but does not contain hydroxyl group. Accepted Answer: Ammonia (NH3) is a weak base, which does not have hydroxyl group in its formula but it gives OH- ions when it reacts with water.